Querying Spatial Resources. An Approach to the Semantic Geospatial Web

The research community has begun an effort to investigate foundations for the next stage of the Web, called Semantic Web [1]. Current efforts include the Extensible Markup Language XML, the Resource description Framework, Topic Maps and the DARPA Agent Markup Language DAML+OIL. A rich domain that requires special attention is the semantics of geospatial information. In order to approach the Semantic Geospatial Web, a mediation system for querying spatial and non-spatial information is presented in this paper. The spatial information is represented in the Geographical Markup Language (GML). GML is an XML encoding developed by the OpenGIS Consortium for the transport and storage of spatial/geographic information, including both spatial features and non-spatial features. In order to integrate spatial information from several spatial XML documents (GML), we have based our work on the Community Web Portal concept with RDF and RQL, a declarative language to query both RDF descriptions and related schemas.